1. Field
The invention relates to a glossoplasty implant tension relief system and the use thereof as a method for treating a condition of an airway of a patient.
2. Description of the Related Art
Obstructive Sleep Apnea (OSA) is a sleep disorder that affects millions of people worldwide. For example, approximately 17 million people in the United States and approximately 20 million people in Europe are affected by OSA. In fact, many patients who have sleep apnea have not yet been diagnosed.
OSA is a condition characterized by frequent obstruction of an individual's airway during sleep. People with OSA may exhibit symptoms including excessive daytime sleepiness, loud snoring, labored breathing, morning headaches, loss of energy, lack of concentration, and irritability. For people experiencing OSA, their tongue may be displaced posteriorly during sleep as a consequence of reduced muscle activity. The displaced tongue may push the soft palate posteriorly and may seal off at least portions of the airway.
Untreated OSA has been associated with serious health consequences such as hypertension, myocardial infarction, cerebrovascular disease, cardiac arrhythmias and sudden death. Treatment of OSA can lead to the improvement of patient symptoms and the improvement of key respiratory variables, such as, for example, the Apnea/Hypopnea Index (AHI) and the lowest oxygen saturation (LSAT).
Continuous Positive Airway Pressure (CPAP) devices are often used as first-line treatments and are the most common treatments for OSA. Although CPAP therapy is highly effective in treating OSA if used properly, patient compliance with these devices are low due to several reasons. For example, nasal masks may be ineffective for some patients, such as those who sleep with their mouths open. Patients may also experience discomfort and the inability to sleep while using the CPAP device. The use of CPAP can lead to other complications, such as local skin irritation, nasal and throat dryness, and eye irritation. More than 50% of diagnosed OSA patients do not adequately use CPAP. Accordingly, patients often abandon therapy during the first 2 to 4 weeks of treatment.
Alternative treatments for OSA include surgical treatments, which avoid problems with patient compliance. The most common current surgical therapies for OSA targets the soft palate and are very painful for patients. The placement of the tongue is a major factor of OSA and there are currently few surgical options to treat tongue collapse.
Implantable devices (e.g., Aspire Advance™ System, Medtronic/InfluENT Repose® Tongue Suspension) have been developed to prevent collapse of the tongue into the airway during sleep. These devices are intended to offer the treating physician a means to surgically treat obstructive sleep apnea in appropriate patients. Generally, some of these devices bias at least a portion of the base of the tongue in a generally anterior/lateral direction to prevent obstruction of the airway. This bias may be created by changing the distance or tension between a portion of the patient's tongue and the patient's mandible.
The Advance™ System, an example of which is shown in FIG. 1, consists of a soft tissue anchor 2, which is delivered into the genioglossus muscle 7 with a specially designed access and delivery system, and an adjustable bone anchor 4, which is attached to the base of the mandible 3 with standard bone screws 5. The tissue anchor 2 is attached to the bone anchor 4 with a tether line 6. The Advance™ System is designed to stabilize the tongue 9 in an anteriorly advanced position, thereby enlarging and increasing the size and stability of the airway 11 in patients diagnosed with obstructive sleep apnea. As the tongue 9 is stabilized, the compliance of the tongue 9 in the anterior/posterior direction is reduced and increased airway stability is achieved.
The Repose Tongue Suspension, an example of which is shown in FIG. 2, is attached to the base of the mandible 3 with standard bone screws 12 (see FIG. 3 for clearer view). A suture loop 18 is connected to the bone anchor 10. One end of the suture loop 18 is inserted through two locations 14, 16 in the posterior portion of the tongue 9. The two ends of the suture loop 18 are then tied to advance and stabilize the genioglossus muscle to prevent the tongue from falling back and obstructing the patient's airway.
Although tongue implants may be effective in preventing the collapse of the tongue into the airway, there are problems associated with the current tongue implants. Tongue implants that engage soft tissue have to contend with passive and active states of the tongue. During sleep, the genioglossus muscle, which runs from the front of the lower jaw into the tongue from tip to base, has a range of activation states. This range includes being mostly passive during deep sleep to being partially activated during light sleep. In these states, a device only needs to support the passive weight of the tongue, which may be one or two pounds. The tongue, in a passive state, does not become an obstruction if it is prevented by the implant device from collapsing into the patient's airway. Furthermore, the force of inhalation does not usually pose a problem for the implantable device. That is, the implantable device may perform as intended when the force of inhalation is exerted on the obstructing tongue and the implantable device. In contrast, forces that are generated during swallowing can exceed 5 to 6 pounds. Swallowing is an activity that a patient performs when awake (or during an arousal from sleep) and does not usually result in airway obstruction. However, the implant must nevertheless retain its properties and position during activities, such as swallowing, that generate forces on the tongue and the implant device. As such, the devices must have an adequate and flexible design margin that allows them to operate in such extreme cases. The devices must also be able to be adjusted before, during, and/or after the device has been implanted into the patient such that the device can be customized for the patient and can accommodate changing conditions.
This range of forces that are exerted on the implant devices poses a challenge for existing devices. In some situations, soft tissue of the tongue can be damaged due to small tissue volume that is captured by the tissue anchor when extreme forces are exerted on the device. Although there are implants that are designed to operate in extreme forces, these devices tend to be larger, bulkier, and more difficult to implant and deploy than their smaller, conventional counterparts. Thus, there is a need for an improved implant system.